GST Compliance – Register & Activate STAK

Registering & Activating STAK (Single Time Authentication Key)

Edition: September 2025
Disclaimer: This manual is for compliance facilitation. It does not substitute statutory provisions, notifications, or circulars. Taxpayers must verify with the CGST/SGST Acts, Rules, and GSTN updates.

✍️ Preface

The GST system provides STAK (Single Time Authentication Key) through the GST Secure OTP mobile app. This feature is mainly available for composition taxpayers, enabling them to file Form GST CMP-08 by using the “File with STAK” option.

This manual consolidates the law, registration and activation process, FAQs with statutory basis, and a compliance checklist.

📑 Table of Contents

1. Law Basis for STAK

2. Pre-Requisites for STAK

3. Step-by-Step Registration & Activation

4. Deactivation of STAK

5. FAQs (with Basis)

6. Compliance Checklist (Fillable Format)

⚖️ 1. Law Basis for STAK

• Rule 26, CGST Rules, 2017 – Authentication of documents can be done via DSC, EVC, or other notified methods.

• GSTN Guidelines – Introduced STAK for composition taxpayers to simplify compliance.

📌 2. Pre-Requisites for STAK

• Mobile device with GST Secure OTP app installed.

• Valid PAN and mobile number registered on GST Portal.

• Android version 5.0 & above (iOS app to be launched soon).

🛠️ 3. Step-by-Step Registration & Activation

STAK Registration (via Mobile App)

1. Download and install the GST Secure OTP app from Play Store.

2. Open the app → Select Services.

3. Enter Mobile Number and PAN → Click Get OTP.

4. Enter OTP received → Registration completed → Verification message displayed.

Activation/Deactivation (via GST Portal)

1. Visit www.gst.gov.in → Login.

2. Go to My Profile > Quick Links > Activate/Deactivate STAK.

3. To activate → Click Activate.

   • If app not installed → Error message displayed.

   • If installed → Success message displayed with Device ID.

4. To deactivate → Click Deactivate → Device ID removed.

❌ 4. Deactivation of STAK

• Taxpayer can deactivate from My Profile > Quick Links > Deactivate STAK.

• Deactivation removes Device ID from GST Portal.

❓ 5. FAQs (with Basis)

Q1. What is STAK?
STAK is a Single Time Authentication Key generated using GST Secure OTP mobile app. (FAQ 1)

Q2. Who can use STAK?
Currently available only to composition taxpayers. (FAQ 3)

Q3. How to activate STAK?
Install app → Register mobile no. & PAN → Activate in GST Portal under My Profile. (FAQ 2,4)

Q4. Can I use a new mobile number?
Yes, but it must be updated first in GST Portal. (FAQ 5)

Q5. Is the app available for iOS?
Not yet; only Android supported currently. (FAQ 6)

✅ 6. Compliance Checklist (Fillable Format)